Google Says It Is Making Progress with Project Treble
Google believes the initial adoption of Android 9 Pie will be quicker than the initial adoption of Android 8 Oreo thanks in part to project Treble. Google launched Project Treble in 2017 with Oreo in an effort to speed up phone makers' ability to push system and security updates to users. Since then, Google has worked with its hardware partners to create a Generic System Image (GSI), drawn directly from the latest AOSP build, and what it calls Vendor Interfaces.
These delineate a clear boundary between the partner's code and Google's code. Google's code can be updated via the GSI rapidly and independently of the vendor code. Moving forward, Google says all devices that launch with Android 9 Pie will be Treble-compliant and can take advantage of swifter system upgrades.
It is this that gives Google the confidence to predict that more devices will be running Pie at the end of 2018 than were running Oreo at the end of 2017.
Developers can use the GSI, too, which will always be based on the most up-to-date version of Android, to test their apps. This should let developers adapt to new Android builds at a faster rate.